1. Field of the Invention
The present invention relates to a component having a micromechanical microphone structure which is realized in a layer construction. The microphone structure includes at least one diaphragm structure which is sensitive to sound pressure and is deflectable essentially in a direction perpendicular to the layer planes of the layer construction; an acoustically penetrable counter-element having through holes, which is formed above or below the diaphragm structure in the layer construction; and a capacitor system for detecting the excursions of the diaphragm structure.
2. Description of the Related Art
MEMS (Micro-Electro-Mechanical-System) microphones of the type discussed here have been known for years and are employed within the framework of widely varying practical applications.
MEMS microphones are common which have a flat diaphragm structure that is parallel to the chip or substrate plane and is excited to vertical (out-of-plane) vibrations by exposure to sound on the front or back side. The signal acquisition is generally carried out capacitively. To that end, disposed on the diaphragm structure is an electrode which, together with a further electrode on a stationary counter-element, forms a capacitor system, so that excursions of the diaphragm structure produce a change in capacitance of this microphone capacitor.
The larger the diaphragm surface, the more sensitive the diaphragm structure is with respect to changes in pressure or acoustic excitation, and the larger it is possible to dimension the surface area of the electrodes of the capacitor system, in order to attain the greatest possible change in capacitance in response to a given diaphragm excursion. For this reason, high microphone sensitivity and the miniaturization of the component are only conditionally compatible with each other. In addition, the production, adjustment and conditioning of large, self-supporting, thin layers as needed for microphone diaphragms are associated with considerable expenditure for development and processing.